Basically his thesis is that when a government collapses during a crisis usually the external crisis is just a stressor revealing the internal crisis. And that internal crisis is usually a long standing erosion of some quality that eventually will fail during an external crisis. So for instance, in the Roman empire, the long term rot in the legions allowed the invading Germans and Huns to knock over the façade of military might.
It’s a very well written essay and might give people an idea of how we might see the Global American Empire begin to come apart. America’s dominance on the world scene was predicated on the combination of American dominance in military, industrial and financial matters. Now all three of those areas have been undermined by its own doing. The Ukraine crisis may be the stressor that reveals America’s decline and maybe collapse.